Relatives of passengers aboard the missing Malaysia Airlines plane said they had received the data report used to determine the path of the plane. Photo: Wu Nan

Malaysia’s Department of Civil Aviation and British satellite firm Inmarsat on Tuesday released the data used to determine the path of missing Malaysia Airlines flight 370, following mounting calls from passengers’ relatives for greater transparency.

Relatives of passengers on the missing jet said they had received the data report, comprising 47 pages of raw satellite data, compiled by Inmarsat and Malaysian officials and they published it on their Facebook page.

The Department of Civil Aviation (DCA) said in a statement it had worked with Inmarsat to provide 47 pages of data communication logs recorded by the British satellite operator, as well as explanatory notes for public consumption.

Analysts said it would take time to draw any conclusions from the raw, ”highly technical” data.

The data communications log comprises 14 pieces of data from seven “handshakes,” or pairs of numbers, between the aircraft and the satellite, Inmarsat said last week. One number is time information, the other is frequency.

Some family members of the 239 passengers and crew on board have been demanding Malaysia release the data so that independent experts can verify it.

The Boeing 777 disappeared on March 8 during a scheduled service between Kuala Lumpur and Beijing. Officials, relying in part on the Inmarsat data, have said they believe the plane ended up over the southern Indian Ocean, where it crashed into the sea.

Nothing has been found despite weeks of extensive searches at the surface and on the seabed.

Authorities believe the plane was flown deliberately off course, but are still investigating the cause of the disappearance.

Leading theories being probed by investigators include a possible hijacking, rogue pilot action or mechanical failure.

This is the information released to the families of the satellite data communication logs.

The highly technical numerical data used the Doppler effect - the change in frequency of waves from a moving object - to decipher the Boeing 777’s final flight path.

Inmarsat plotted models of the flight’s route by measuring the Doppler effect of the hourly satellite 'pings' from the aircraft, giving corridors arcing north and south along which the plane could have flown for at least five hours.

Despite the plane’s communication systems being switched off, satellite pings were still bouncing back from the aircraft.

The pings are sent from a ground station to a satellite, then onto the plane, which automatically sends a ping back to the satellite and down to the ground station.

They do not include global positioning system (GPS) data, time or distance information, so the British satellite operator measured the amount of time it took for the pings to be returned.

They then compared those figures to data from other Malaysia Airlines planes and similar flight routes, which definitively showed the plane could only have been going down the southern corridor, and would eventually have run out of fuel.

They established an “extraordinary matching” between Inmarsat’s predicted southern path and readings from other planes on such routes.

Inmarsat’s interpretation of the data was subsequently verified by the international investigation team, which includes the DCA, the US National Transport Safety Board, Britain’s Air Accidents Investigations Branch, and China’s Aircraft Accident Investigation Department.

But, with no sign of the plane found since its disappearance on March 8, relatives were sceptical.

“There is no mention on why they are so sure the Inmarsat data is highly accurate and reliable, to the extent that they have thrown all resources there,” the families said in a May 20th report to the governments of Malaysia and Australia, which is coordinating the search efforts.

Shukor Yusof, an aviation analyst with Malaysia-based Endau Analytics, said that the satellite data was “highly technical” and required an expert to decode.

“There are very few people who can make head or tail as to what the numbers indicate. To me as a layman, it looks like a sequence of signals that were given out by the aircraft possibly indicating its flight path,” he said.

Greg Waldron, Singapore-based managing editor with aviation publication group Flightglobal, said the satellite data was consistent with what Inmarsat had previously revealed.

“Basically it shows the timings of the handshakes of the plane with the satellite over the Indian Ocean,” he said.

“But I would not dare to guess if they are searching in the right place. The fact that they are using this type of data shows how desperate the search for the plane is.”

The DCA has previously stressed that satellite data was just one of several elements being examined by investigators.

Malaysian authorities have been tight-lipped on details, saying they can only divulge information once it has been verified and when its release will not affect ongoing investigations into the plane’s disappearance.

Australia, which is leading the hunt in the Indian Ocean, has committed up to US$84 million towards the search operation over two years.